In the automotive industry, the increasing number of product variants requires a high degree of flexibility, offering new applications for additive manufacturing processes. A promising and cost-effective approach is the hybrid additive manufacturing of tool components using directed energy deposition (DED). A key factor in the process is the laser power, as the temperature gradient between substrate and additive build-up has a significant influence on the formation of cracks and the contour accuracy of the component. In this paper, a laser power control system is investigated with the aim of keeping the melt pool temperature constant to reduce geometric deviations and residual stresses resulting from excessive heat input into the component. For this purpose, welding specimens are manufactured additively, followed by an optical measurement and a metallographic analysis to identify part defects. The results are used to produce a tool component with an optimized hybrid additive manufacturing strategy.

Laser cladding technology using wire is a modern technique for surface enhancement and repair. This study investigates the cladding process using steel 42CrMo4+QT as the base material and stainless steel 316L as the additive material. A pyrometer and infrared camera were used for monitoring the process. The pyrometer provided real-time measurements of the melt pool temperature, while the thermal camera provided a detailed view of the heat distribution and cooling dynamics. A key focus of the research was to analyse how heat accumulation affects the measured quantities and influences the technology outcome. By investigating the interplay between thermal parameters, heat accumulation and cladding quality, the study identifies critical quantities for optimising process control. These findings will help to advance the application of LMD wire technology in industrial surface engineering.

Material extrusion is a widely used AM process and is gaining more acceptance in industry applications due to its material variety, flexibility, and low cost. However, its usage is limited by a process-related anisotropy caused by insufficient interlayer bonding due to reduced temperature in the process zone. To enhance layer adhesion, an adaptive laser preheating system is integrated in a conventional printhead around the extrusion nozzle. The setup with eight fiber coupled diode laser allows preheating in feed direction and investigation of various intensity profiles. The article describes the experimental setup and significant improvements achieved. Laser preheating with different intensity distributions (spot, sickle or ring shaped) show an incasement of up to 85 % of the mechanical properties in the build-up direction. However, due to the additional energy input by the laser, controlled cooling of the workpiece becomes a crucial factor and is investigated as well.

In laser powder bed fusion (PBF-LB/M), the adjustment of the microstructure by parameter variation is limited by process stability and it’s resulting part quality. By combining PBF-LB/M with ultrashort laser ablation, these limits can be exceeded by transiently involving additional heat dissipation structures or slits, which act as heat barriers. These additional structures can be removed during build-up.

The microstructure adjustment in AlSi10Mg components manufactured by combined additive and subtractive (AddSub) laser material processing was the focus of experimental and numerical investigations. Different heat dissipation structures with varying geometries and ablation strategies were manufactured and subsequently metallographically analyzed including hardness measurements. The employment of these structures leads to an altered local temperature field, consequently affecting the solidification conditions. A comparison was made between conventionally manufactured parts by means of PBF-LB/M and those produced using the aforementioned methods.

In PBF-LB/M, pulsed modulation leads to higher cooling rates and refined microstructures due to altered solidification conditions. Introducing laser-off times suppresses heat accumulation and improves manufacturing accuracy. However, it also decreases productivity due to laser-off times and lower scan speeds compared to conventional PBF-LB/M processing. Achieving comparable build-up rates requires a holistic approach to process and system technology development. Fraunhofer ILT has explored pulsed melting in PBF-LB/M using an ultrafast laser beam deflection, establishing a pulsed melting process with a continuously emitting cw laser source. Experiments indicate that traditional parameter settings must be reevaluated, particularly regarding spatial and temporal interactions of multiple melt pools, the powder layer, and shielding gas flow. This article presents initial investigations and discusses the process observations and analysis of first samples.

Here, we explore advanced technical solutions for integrating laser micro-machining processes into an SLM 250 machine, creating an efficient and precise hybrid system. The integration involves adding an IR fiber laser (nanosecond or picosecond) with 30-100W power, coexisting with the CW fusion laser. Both utilize the same beam shaping and movement equipment, including a galvanometric head and F-Theta lens. We've modified the control system to enable swift transitions between SLM and micro-machining modes between layers, enhancing process synchronization. To achieve extremely precise control over laser beam position, size, and shape, we've developed a tool capable of characterizing both continuous and ultrashort pulse laser beam profiles up to 100W. The integrated micro-machining process is being tested to improve layer surface roughness and precision, particularly for micro-channel resolution. This hybrid approach promises to significantly enhance the capabilities of additive manufacturing, offering new possibilities for creating complex, high-precision components with superior surface quality.